A woman arrested in Phoenix for domestic violence and assaulting a police officer slipped out of her handcuffs and hung herself with a shoelace from a vent in the back of a police van, authorities said.

The woman was rushed to hospital unconscious Thursday after the officers driving the van tried to revive her, but she was not expected to survive, a Phoenix police statement said.

It did not give her name or race.

The woman was being taken to jail after being arrested early on Wednesday and was the only person in the back of the van, the statement said. An investigation into the incident had begun.

Last year, Sandra Bland, an African-American woman, was found dead with a trash bag around her neck in her cell at a jail in Waller County, Texas, where she was arrested at a traffic stop. Authorities said her death was a suicide.

The case sparked protests and raised questions about whether she was jailed and mistreated because of her race.

A committee this year recommended sweeping changes for Waller County jails, including better mental health screening.